There are multiple steps:

• Install Apache and PHP
• Install Apache
• Install the necessary PHP components

sudo apt-get install php php-gd php-xml php-json -y

sudo systemctl enable --now apache2

For the latest Staple version:

wget https://download.dokuwiki.org/src/dokuwiki/dokuwiki-stable.tgz

For the Release Candidate Version:

wget https://download.dokuwiki.org/src/dokuwiki/dokuwiki-rc.tgz

tar xvzf dokuwiki-stable.tgz

Move and rename the newly-created directory:

sudo mv dokuwiki-XXX /var/www/html/dokuwiki

Copy the sample .htaccess file:

sudo cp /var/www/html/dokuwiki/.htaccess{.dist,}

sudo chown -R www-data:www-data /var/www/html/dokuwiki

At the moment, Apache has no way of knowing about the new installation.

• To make it aware, create a configuration file for DokuWiki.

sudo vi /etc/apache2/sites-available/dokuwiki.conf

…and populate that file with:

ServerName dokuwiki.example.com
DocumentRoot /var/www/html/dokuwiki
 
AllowOverride All
Require all denied
 
Order allow,deny
Deny from all
 
ErrorLog /var/log/apache2/dokuwiki_error.log
CustomLog /var/log/apache2/dokuwiki_access.log combined

Save and close the file.

sudo a2ensite dokuwiki

sudo systemctl reload apache2